The angle at which solar radiation strikes an energy converting unit (e.g. a group of photovoltaic cells on a solar panel) can significantly affect the unit's ability to convert solar energy into electrical energy. Optimally, this angle of incidence for solar radiation will be ninety degrees (i.e. an energy converting unit operates most efficiently when oriented so that solar radiation is directed at a right angle, perpendicular to the surface of the energy converting unit). To do this, the energy converting unit is required to move to track the sun. This, however, may be difficult or impractical to achieve. One reason for this difficulty is the continuous movement of the sun throughout the day. And, a second reason for this difficulty is that a solar panel must be continuously reoriented while not interfering with other activities taking place in the vicinity of the solar panel.
Although the efficiencies of energy converting units are diminished as the angle of incidence deviates from perpendicular, the diminution of efficiency is minimal with small deviations. On the other hand, with relatively large deviations from perpendicular, the diminished effect quickly becomes significant. To minimize this loss and, conversely, to maximize system efficiency, the structure on which the energy converting unit is mounted (e.g. a solar panel) must effectively track the movement of the sun. Operationally, this must be done in compliance with two considerations. These are: azimuth and elevation.
In order to effectively track the movement of the sun, it is clear that both the azimuthal movements and elevation considerations for a solar panel are important. For example, the panel must first be pointed in the proper azimuthal direction (i.e. toward the sun). Secondly, once the azimuth is established, the panel must then be inclined in elevation to optimize (maximize) the angle of incidence. On the first point (i.e. azimuthal tracking), in comparison with a stationary solar panel, it has been determined that the overall efficiency of energy converting units can be improved by around twenty percent when the solar panel azimuthally tracks the sun. On the second point, for latitudes of the United States, in comparison with a horizontally oriented solar panel, an inclination angle for elevation of about ten to twenty degrees has been determined to be generally optimal.
To effectively track the movement of the sun described above, it is necessary to constantly reposition a solar panel. Such constant repositioning presents difficulties when considering the placement of a solar panel. As a solar panel is often part of an array of multiple solar panels, consideration must be given to the location of other solar panels as the motion may cause two panels to impact one another. The impact of two solar panels may cause damage to the panel or disrupt the ability of a panel to maintain an optimal angle of incidence with the sun. A further consideration for the movement of a solar panel is the footprint of the solar panel, meaning the area of the ground beneath the solar panel. As solar panels become more prevalent in public areas, designers must ensure the footprint of the solar panel remains substantially stationary. If the footprint of the solar panel is allowed to move, the solar panel may interfere with activities being conducted in its vicinity. For example, rotating a solar panel used to power lighting in a parking lot may obstruct the movement of fire trucks and other safety vehicles in the parking lot.
In light of the above it is an object of the present invention to provide a system for continuously reorienting a solar panel to track the sun, and to thereby maximize solar energy utilization. Another object of the present invention is to provide a system for continuously reorienting a solar panel while maintaining a substantially stationary footprint. Yet another object of the present invention is to provide a system for continuously reorienting a solar panel that is easy to use, is relatively simple to manufacture, and is comparatively cost effective.